Sled board with tracking bottom

ABSTRACT

The invention features a soft foam sled board for use by a sitting or kneeling rider to slide over a snow or ice covered surface. The sled is prepared from a shaped polyethylene foam core, and at least the bottom surface of the core is covered by a slick, polyethylene film/polyethylene foam sheet laminate which provides little frictional resistance between the sled board and sliding surface, and provides an impervious outer surface to the board so as to resist puncture and water infiltrate. The sled board has one or more rails, ribs, or fins embedded below the body weight of the rider so as to either protrude from, or jut into, the board. The fins enhance the ability of the sled board to travel down the hill in a straight, forward direction.

BACKGROUND OF THE INVENTION

[0001] The invention relates to a sports board for sliding on surfacessuch as snow or ice.

[0002] Due to their comfort, light weight, and attractive designs, softfoam sled boards have become popular for sliding in a kneeling, prone,or sitting position on snow or ice. Soft foam sled boards have beenprepared with a polyethylene foam core and a slick film outer skin thatis puncture resistant and impervious to water. These boards have theadvantage of a slick surface, which creates less drag and promotes quickrelease from the sliding surface, but also have a flat, planar bottomsurface which is prone to lateral motion. Thus, sled boards of soft foamconstruction suffer from an inability to keep a straight course.

[0003] It is thus an object of the invention to provide a soft foam sledboard that holds a substantially straight, forward course when used on asliding surface such as snow or ice.

SUMMARY OF THE INVENTION

[0004] The invention generally features a soft foam sled board having aone or more tracking rails extending longitudinally below the portion ofthe sled that supports the body weight of the rider. A ‘tracking rail’can be a rail, rib, or fin that protrudes from the under surface of theboard; it can also be a channel or groove that juts into, or cuts into,the under surface of the board. The tracking rail enhances the abilityof the sled to travel straight in a forward direction, while retainingthe advantages of flex and cushioning, or shock absorption, that areattributes of the air pockets trapped within the soft foam coreconstruction. The sliding device has one or more rails, preferably twoor more rails.

[0005] Thus, the invention features a sliding device having a soft foamcore, a slick skin covering at least the under surface of the device,and one or more tracking rails on the under surface and below the ridersupport region, of the sled body.

[0006] The rail is an integral part of the sled board and is attached orsecured to the under surface. The rail is configured to be one with thesled board during manufacture and is attached or secured to the sledboard, so that the rail cannot come apart or be separated from theremainder of the sled board. The rail is secured integrally to the sledboard by any method or material that can secure the foam rail to a softfoam board, for example, an adhesive that permanently adheres to a softfoam polyethylene or to a polyethylene sheet or film. Preferably, therail is secured integrally in the sled board by heat lamination.

[0007] The a sliding device of the invention is a sled board that trackswell in a straight, forward direction, especially when used in thedownhill direction on a downward slope. The sled board of the inventionhas a soft foam construction and can be referred to as a “soft board.” Asled board includes an elongate member having a self-supporting, softfoam core, and at least one longitudinally-extending rail. The elongatemember includes an upwardly-curved leading end portion having a leadingedge, and includes a body portion having a trailing edge, an uppersurface, a rider support region, and a substantially planar undersurface. The rail is integrally attached to the under surface, below therider support region of the body portion of the elongate member.

[0008] The rail is aligned substantially parallel to the longitudinalaxis of the sliding device. The rail can extend along a portion of thelength of the bottom of the sled; for example, the rail(s) is one to twoinches in length. Alternatively, the rail(s) can extend approximately athird, a half of the length of the sled, or over the full length of thesled. Preferably, the rail(s) extends along the back portion of thesled. More preferably, the rail(s) extends along the portion of the sledthat is below the body weight of the user(s). There can be onelongitudinal rail below the body weight of the rider, or two or morelongitudinal rails.

[0009] The rail is beneath the slick bottom skin, or can be on top ofthe slick skin.

[0010] Preferably, the sliding device has an upturned ‘nose’ at theleading end portion. The upturned or “flipped-up” leading end has theadvantage of preventing one end of the sled from acting as a brake bydigging into the snow and stopping the sled.

[0011] In one embodiment, the sliding device has one or more hand gripsor handles to which a rider may hold during use. Preferably, the slidingdevice has a pair of hand grips on opposite sides of the sled. Morepreferably, the handles are located adjacent to the location of therider support region, or adjacent to and slightly forward of the ridersupport region. In another embodiment, where the sliding device has twoor more pairs of handles so as to be held by two or more riders seatedtogether on the sled, the handles are adjacent to, or adjacent andslightly forward of, the respective rider support regions, or of thecombined rider(s) support region. Where the sliding device has one ormore handles, the tracking rails are positioned so as not to be belowthe handgrips. In use, the rider pulls upward on the handgrips. Were therails to be placed beneath the handles, the rails would be pulled upwardby the upward force on the handgrip, thereby lifting the rails away fromthe sliding surface. This would decrease, or break, contact between therail and the sliding surface, and reduce tracking efficiency.

[0012] The sled board of the invention can optionally further include astrap. The strap has two ends. One end of the strap can be attached tothe sled board. Preferably, the strap is attached to the leading edge ofthe sled, such as to a hole or indentation formed in the leading endportion. Alternatively the strap can be attached to one or more handgrips of the sled. The second end of the strap can be used to pull thesled, for example to pull the sled up a hill between uses. The secondend of the sled can be gripped by the user, or can be attached to theuser, such as to the wrist of the user. Preferably, the strap has a loopat the second end that can fit around the wrist of the user.Alternatively, the second end of the strap can include a means forsecuring the strap to a garment of the user, such as a snap, button, orre-attachable adhesive, including without limitation, a VELCRO® (Velcrois a registered trademark of Velcro Industries B.V. of Curacao,Netherlands) adhesive.

[0013] By “sled board” is meant an apparatus for sliding on snow or ice,preferably on a downward slope. Such devices are commonly referred toas, for example, sleds or toboggans.

[0014] The longitudinal sides of the sled can be straight.Alternatively, the sides of the sled can be shaped so as to permit thesled to curve when the side of the sled is engaged into the snow.Preferably, the sides of the sled are shaped with one or more concavecurves or with one or more convex curves. The curvature(s) on the twosides of the sleds can be symmetrical. Alternatively, the curvature(s)on the two sides of the sleds are asymmetrical. Optionally, the sides ofthe sled can be curved so as to give the sled a snowboard-likeappearance.

[0015] In one embodiment, the sliding device can have a shape similar toa traditional freestyle snowboard, but in contrast to a snowboard whichis made to be used in a standing position, the sliding device of theinvention is intended for a kneeling, prone, or seated user. The sled ofthe invention does not require the stiffness or rigidity necessary for astanding rider.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016]FIG. 1 is a perspective view from above a sled board of theinvention.

[0017]FIG. 2 is an illustration of the top side of a sled board of theinvention.

[0018]FIG. 3 is an illustration of the bottom side of an embodiment ofthe sled board of the invention that features two protruding rails withflat ridges.

[0019]FIG. 4 is a side view of an embodiment of the sled board of theinvention.

[0020]FIG. 5 is a cross-sectional view of the sled board of FIG. 3,shown at cross-section 5.

[0021]FIG. 6 is a cross-sectional view of the sled board of FIG. 3,shown at cross-section 6.

[0022]FIG. 7 is an illustration of the bottom side of an embodiment of asled board of the invention that features two protrudingtriangular-peaked rails.

DETAILED DESCRIPTION

[0023] FIGS. 1-7 generally depict a sliding device, or sled board, ofthe present invention. Sled board 1 typically includes elongate member2, configured to slide on any sufficiently slippery surface, such assnow, ice, grass, metal, or water on a water slide. Preferably, thesurface is covered with snow or ice, and has a downward slope.

[0024] As illustrated in FIG. 1, elongate member 2 includes asubstantially flat, or planar, body portion 3, and a leading end portion4. In use, a rider sits or kneels on rider support region. Rider supportregion is typically that area of body portion 3 on which a rider sits,kneels, or lies prone when sliding on sled board 1. Preferably, the areaof rider support region is inward of one or more handgrip(s) 8,posterior to leading end portion 4, and anterior to trailing edge 24.Leading end portion 4 has an inward end that is positioned to connectto, or preferably to be continuous with, the forward end of body portion3. Leading end portion 4 typically extends outward from body portion 3with an upturned shape, so as to avoid digging into the sliding surfacewhen sled board 1 moves forward.

[0025]FIG. 2 is a top view of a sled board of the invention. Elongatemember 2 has an upper surface 6. Optionally, upper surface 6 has a topskin. FIG. 1 illustrates elongate member 2 with outer edge 20, whichincludes left and right side edges 21 and 22, and leading and trailingedges 23 and 24. Side edges 21 and 22 are substantially coplanar withbody portion 3, while, due to the upturn in leading end portion 4,leading edge 23 is higher than the plane of body portion 3. Preferably,leading edge 23 is at least one inch higher than body portion 3, and canbe, for example, 6 inches higher, or even 2 inches higher, or 5 or 10inches higher.

[0026] Trailing edge 24 can be straight, can have a convex curve, or canhave two or more convex curves, known in the art as bat tails.

[0027] Typically, the shape of leading and trailing ends 23 and 24 isrounded. Alternatively, the leading and trailing ends 23 and 24 may bestraight, or polygonal, or any desired shape.

[0028] Typically, left and right sides 21 and 22 are straight.Alternatively, the sides of the sled may be shaped so as to permit thesled to curve when the side of the sled is engaged into the snow.Preferably, sides 21 and 22 are shaped with one or more concave curves.Alternatively, sides 21 and 22 have one or more convex curves or have acombination of concave curves and convex curves. The curvature(s) on thetwo sides of the sleds can be symmetrical. Alternatively, thecurvature(s) on the two sides of the sleds are asymmetrical. Optionally,the sides of the sled may be curved so as to give the sled asnowboard-like appearance.

[0029] Elongate member 2 typically includes a bevel or outer edge 20.Alternatively, the outer edge can be rounded, or it will be appreciatedthat the outer edge 20 of elongate member 2 may not include any bevel atall.

[0030] One or more hand grip(s) or handles 8 can be affixed to the sledboard 1 for a rider to grab onto during use. Preferably, the sled board1 has a pair of handles 8 on opposite sides 21 and 22 of the sled board1. More preferably, the handles 8 are located adjacent to the placementof the rider's position at the rider support region; or the handgrips 8are located adjacent to and slightly forward of the rider supportregion. In another embodiment, the sliding device has two or more pairsof handles 8, so as to be held by two or more riders seated together onthe sled, on the outer edges of the sled board 1 adjacent to a combinedrider support region.

[0031]FIGS. 3 and 7 show the bottom side of two embodiments of the sledboard 1 of the invention. Elongate member 2 has an under surface 7.Optionally, under surface 7 has a bottom skin. Under surface 7 includesleading under surface 7 a, typically underlying leading upturned endportion 4. Under surface 7 further includes body under surface 7 b,typically extending from the inward end of leading under surface 7 a totrailing edge 24. The body under surface 7 b is relatively planar to thesurface over which the sled board 1 slides. Typically, the leading undersurface 7 a is shaped in a continuous curve originating at an inward endof the leading upturned end portion 4. Alternatively, the upturnedbottom regions may be straight, polygonal, or curved in another shape.

[0032] The ability of sled board 1 to track in a forward direction ismarkedly improved by placing at least one rail 9 on the underside of therider support region. Rail 9 is an integral feature of body undersurface 7. In FIG. 3, rail 9 is a raised rail, protruding from the bodyunder surface 7 b. Alternatively, rail 9 can be a longitudinal groove orchannel recessed in body under surface 7 b. Where a bottom skin ispresent on under surface 7, rail 9 is preferably between the foam coreof body portion 3 and the bottom skin. In an alternative embodiment,rail 9 is on top of the bottom skin.

[0033] A critical aspect of the invention is that, due to the highdegree of flex of a soft foam board, the rail(s) must be positioned sothat at least a portion of the rail 9 is located below the rider supportregion, which is the portion of the sled board 1 below the body weightof the rider. The placement of the rail 9 is less critical on supportsprepared from materials having more rigidity, like wood, fiberglass, orhard plastic.

[0034] The shape of rail 9 is characterized by its shape, including, asappropriate, length 10, width 11, and depth or height 12. The shape ofrail 9 can be triangular, can be rectangular, or can be a variant. InFIG. 2, rail 9 has a flat top and has sides that bevel with an inwardlydirected slope. In FIG. 7, rail 9 can have a triangular shape, so as tohave a triangular peaked top.

[0035] Rail 9 extends along under surface 7 of body portion 3 in alongitudinal direction. The length and exact location of the rail 9 canbe varied, as long as the rail 9 is principally located below the ridersupport region, so that the body weight of the rider keeps rail 9 inslidable connection with the sliding surface. Rail 9 can extendlongitudinally over all of body portion 3. Alternatively, rail 9 mayextend longitudinally over only a portion of the rider support region ofbody portion 3. Thus, the forward end of rail 9 can be at the junctionof leading end portion 4 and body portion 3, or the forward end of rail9 can be in the area of hand grip 8, or can be posterior to handgrip 8.The rear end of rail 9 can be at trailing edge 24. Alternatively, therear end of rail 9 can be positioned at the posterior side of the ridersupport region, or can be between the posterior side of the ridersupport region and trailing edge 24.

[0036] The width of the rail can vary along the length of the rail, forexample, from {fraction (1/16)} inch to 3 inches. Preferably, the railhas an angular shape varying from 20 to 90 degrees (20-90°) off theplanar surface of the sled board.

[0037] Generally, tracking performance can be improved by increasing thedepth of the rail, which is the distance between under surface 7 and therail bottom surface 14. The rail can have a thickness ranging from,e.g., 0.125 to 2.0 inches, preferably 0.25 to 1.0 inches, and morepreferably from 0.5 to 0.75 inches thick.

[0038] Where sled board 1 has two or more rails 9, the rails aregenerally parallel. The distance between the central point, or peak, ofthe rails is generally between, for example, 2 inches and 16 inches,preferably 10 inches. The rails should be arranged so as to distrubutethe body weight of the rider over the rails.

[0039]FIG. 4 is a side view of a sled board of the invention. Leadingend portion 4 typically extends outward from body portion 3 with anupturned shape. Preferably, leading end portion 4 has a continuous,upwardly curved shape. The leading end portion 4 may have a polygonalshape, or may have another continuous curved shape, or may have adiscontinuous curved shape. The leading end portion 4 can have a radiusof curvature or, alternatively, may be kinked.

[0040]FIG. 5 is a cross-sectional view of the sled board 1 of FIG. 3,shown at cross-section 5.

[0041]FIG. 6 is a cross-sectional view of the sled board 1 of FIG. 3,shown at cross-section 6.

[0042] The dimensions of sled board 1 can be adjusted to the size of theintended rider. Generally, a sled board 1 is approximately 36 to 82inches in length, for example, 36 to 40 inches or 41 inches for a juniorrider, or 42 to 50 inches, preferably 45 or 46 inches for an adultrider. Preferably, a sled board 1 designed for a single rider isapproximately 36 to 46 inches in overall length, while a sled board 1designed for two or more riders may be 50 to 85 inches long or longer,preferably 54 inches long, or 80 inches long.

[0043] Generally, a sled board 1 is approximately 20 to 25 inches inoverall width, preferably 21 or 24 inches in width. The sled board 1 canhave a foam core depth of approximately ½ to 2 inches and preferably hasa depth of 1 inch.

[0044] Method of Manufacture

[0045] In manufacture, the sled board of the invention is preparedsubstantially as follows. The elongate member is typically made of ahigher density closed-cell material than the core material of the sledboard, including but not limited to polyethylene, polypropylene, R-cell,or polystyrene. Optionally, the sled board can be made substantially asdescribed in U.S. Pat. No. 4,850,913, issued Jul. 25, 1989, herebyincorporated by reference. For example, in one embodiment of theinvention, elongate member 2 has a shaped core of closed-cellpolyethylene foam, to which a skin is heat laminated. The skin isprepared from a polyethylene film laminated directly to the undersurface of the foam core. Alternatively, the skin is pre-formed from adenser closed-cell polyethylene foam laminated to a polyethylene film.The film/foam skin is made by heat lamination, and is adhered to thelower surface of the foam core and, optionally, to the outer edges ofthe sled board.

[0046] The foam core is a shaped core of closed-cell polyethylene foamplanking, preferably with a density of about 1 to 10 pounds per cubicfoot (pcf), more preferably with a density of about 2 to 4 pcf. The corecan either be made from a single piece of foam planking cut to shape, orit can be composed of a laminate of a plurality of foam sheets eitherheat laminated to each other, or laminated by other methods known in theart, such as polyethylene film lamination. A laminated core is cut toshape similarly to a one-piece core.

[0047] The rail is prepared by cutting a piece of polyethylene foam intoa desired rail shape. The rail piece can be a triangular shape, so as tocreate a rail having a peaked bottom rail surface. The rail piece canhave a substantially rectangular shape, so as to create a flat bottomrail surface. The rail piece can have flat rectangular shape to create aflat bottom rail surface, but with sloped sides, thereby merging theadvantages of the triangular and rectangular designs. Preferably, thefoam used for the rail is denser foam than the foam used for the core ofthe sled.

[0048] The foam rail piece is heat laminated into position on the underside of the foam core. The foam rail piece(s) is positioned on the undersurface of the foam core by lamination. The laminator consists of tworollers that are positioned vertically with a variable gap between themand have a method of applying pressure against each other, like springsor weights. Either roller is driven or in some cases both rollers aredriven. Positioned in the middle of the rollers, but located about 6back from the “pinch zone,” is a heat source. The heat source can be hotair (600 degrees) or a radiant heat source like infrared. The materialsto be laminated are passed above and below the heat source, and thenthrough the pinch rollers which drive the material through at a constantrate of speed. The pinch rollers apply pressure to the melted surfacesof the foam materials, and they consequently stick together.

[0049] A piece of bottom slick skin is adhered to the under side of thefoam core/foam rail unit. At the same time that the slick skin ispassing through the laminator, a piece of #2 MICROCELL® (Microcell is aregistered trademark of Sentinel Products Corp. of Hyannis, Mass.) foamis fed through the laminator on top of the slick skin. The MICROCELL®foam should be at least as thick as the height of the rail; it acts as abuffer to absorb the rail, while maintaining surrounding pressure aroundthe rail, so that the slick skin will bond to the rail-raised undersurface of the sled board body.

[0050] The sled board of the invention has a slippery, i.e., slick,outer skin over substantially all of the bottom of under surface 7 and,optionally, over part or all of outer edge 20. The slick bottom surfaceon the underside and outer edge of the sled board creates less drag andpromotes quick release from the sliding surface. The slick skin givesthe sled board improved performance, superior cosmetic appearance,ability to receive permanent color impregnation of a logo, ability toreceive dry adhesive traction material, decreased water absorption bythe board, and other benefits.

[0051] Preferably, the bottom skin is a thin sheet of polyethylene orsimilar plastic, such as, for example, SURLYN® (Surlyn is a registeredtrademark of E. I. DuPont De Nememours and Company of Willmington,Del.). A sheet of skin, e.g., 10-25 mil, can be extruded onto a ⅛ inchsheet of foam (commonly 4#-8# polyethylene). A material suitable for useas a bottom skin is, without limitation, SLICKSKIN™ (Slickskin is atrademark of Earth & Ocean Sports, Inc. of Redmond, Wash.).Alternatively, the 10 to 25 mil film can be extruded directly onto thecore material without first extruding it to the 4#-8# foam backing. Thepolyethylene film forming the outer skin of the sled board is suitablyabout 1 to 100 mils in thickness, preferably about 10 to 50 mils inthickness. This film can be extruded onto a polyethylene closed-cellfoam sheet having a density of about 1 to 10 pcf, preferably about 4 to8 pcf, and most preferably about 6 pcf. The film may be clear or may becolored during its manufacture. The film is extruded to the foam sheetat about 400° F., as known in the art, and the film/foam laminate is aircooled and taken up on rolls.

[0052] The bottom skin (the ⅛-inch foam sheet and skin combination) isthen laminated onto a core, typically a rectangular core, composed oflower density material, including but not limited to polyethylene,polypropylene, R-cell, or polystyrene. The foam core and the film/foamlaminate are then each heated to about 400° F. on the foam surfaces tobe laminated together. The closed-cells on these surfaces open under theinfluence of heat, and the surfaces are brought together undercompression. The heat and pressure enable a laminate to be formed. Thecore is then reversed, and the unlaminated side is heated and anothersheet of film/foam laminate is similarly laminated thereto. A film/foamsheet is subsequently laminated to the exposed side edges of the board,thus substantially encasing the core in film/foam laminate, or the topsheet is left large enough to wrap the sides. The edge strips or topsheet wrap are also applied by heat lamination and compression. Thepressure may be applied by hand, iron, or roller, or by another methodknown in the art. The board is air-cooled.

[0053] Conversely, this skin could be extruded directly onto the corematerial, without first extruding onto the ⅛-inch carrier sheet of foam.Once the core and the skin are bonded, the plan shape, as shown in thesled from the top view, is fashioned, and the core is contoured tocreate, for example, rounded sides, or a dished middle, or shaped insuch a way as to create a pocket to hold the rider. This inherently flatcore and skin is then laminated or bonded to the top deck. The top deckcan be of polyethylene, but can also be of nylon, polyester,polypropylene, MICROCELL®, or elastomeric metallocene rubber (EMR). Asthe board emerges from the rollers in a hot, malleable state, the noseis curved into an upturned shape and allowed to cool. The perimeter isthen finished off by heat lamination and is then trimmed to create afinished sled. Heat stamps are then applied, and handles 8 are affixedby methods known to those skilled in the art, so as to complete theproduct. Optionally, handles are applied as disclosed in U.S. Pat. No.5,154,655, issued Oct. 13, 1992, hereby incorporated by reference.

[0054] Optionally, the upper surface of the sled board comes in sheetform, ⅛ to {fraction (3/16)} inch thick. It can be #4 polyethylene foam.The sheet is laminated onto the core, and the sides are heat laminatedby hand around the sides. Any embossing is then put into the skin.Another alternative method is to pre-emboss or vacuum-form the sheet andthen laminate it to the core. Color patterns may optionally beincorporated into the film/foam laminate by adding color concentrate ina pattern configuration to the film surface immediately prior tolamination to the foam sheet. This provides a similar patternconfiguration on the board. For example, the color may be appliedbetween the film and foam during the lamination process when the filmand foam sheets have both been unwound from rolls and exposed to heatand are traveling toward the nip of pressure rolls. As the heated sheetspass through the nip of the pressure rolls, heat lamination takes place.

[0055] A logo may be permanently applied to the deck and/or bottom ofthe board. In a non-limiting example, a logo may be permanently appliedto the polyethylene film outer layer, using heat and pressure on aMYLAR® (MYLAR is a registered trademark of E. I. DuPont De Nemours andCompany of Wilmington, Del.) transfer pattern made especially forapplying to polyethylene (Mylar is a polyester film made by E. I. DuPont& Company, Ltd.).

[0056] A foam board of the invention is slick to the touch andparticularly when it is wet, the board is slippery to feel. In order toprovide good frictional adhesion, dry adhesive traction material or waxmay be applied. The dry adhesive traction material is particularlysuitable for applying to the top deck of the board, either substantiallyover the whole surface of the deck or in particular areas, asappropriate. Dry adhesive or wax may also be applied around the edges ofthe board to facilitate handling. Traction material on the upper surfaceof the board facilitates a good grip by the user without impairing thefunctional advantages of the slick bottom surfaces of the board.Suitable dry adhesives are, e.g., TRAC-TOP® (Trac-Top is a registeredtrademark of Earth & Ocean Sports, Inc. of Redmond, Wash.). Preferably,the adhesive is a pressure-sensitive adhesive.

[0057] The materials and design of the board combine synergistically toprovide a slick board with excellent performance characteristics, sincefrictional resistance is decreased and loss in velocity as the boardmoves through the medium is minimized by use of the glossy,non-absorptive surface. The slick polyethylene film skin is resistant topuncturing and impervious to water.

[0058] Appropriate materials for the core also include polyethylenefoam, polypropylene foam, polyurethane foam, and ARCEL® foam (Arcel is aregistered trademark of the Atlantic Richfield Company of Philadelphia,Pa.). Polyethylene foam is the preferred material. The outer film sheetis preferably polyethylene film laminated to a sheet of polyethylenefoam. The polyethylene foam sheet provides strength and cushioning tothe film, and the slick skin formed from the film is laminated to thecore of the board to provide a board having a smooth, glossy surfacewhich glides easily through snow, or over other surfaces.

[0059] The performance characteristics of the board may be varied byvarying the density of the foam core, foam sheet and/or film. Forexample, a sliding device can have a 30-mil thickness of polyethylenefilm forming the skin on the deck of the board and on the bottom of theboard, and a 15-mil thickness of film as the outer glossy surface on theedges of the board. A stiffer board is provided if either the foam corehas a greater density and/or the film skins have a greater densityand/or thickness. The degree of flex of the board can be controlled byvarying the thickness of the foam core and skin, a greater degree offlex being provided by use of less dense foams and thinner films. Inparticular, thickness of the film outer skin is determinative offlexibility of the board.

[0060] In balancing the properties required, the strength of the productmust also be considered, and in general, heavier, thicker materialsprovide the advantage of greater strength, but the disadvantage ofgreater weight and stiffness.

[0061] While the invention has been described above with respect tocertain embodiments thereof, it will be appreciated that variations andmodifications may be made without departing from the spirit and scope ofthe invention.

What is claimed is:
 1. A sled comprising: (a) an elongate member havinga self-supporting, soft foam core, said elongate member comprising anupwardly-curved leading end portion having a leading edge, and a bodyportion having a trailing edge, an upper surface, a rider supportregion, a substantially planar under surface; and (b) at least onelongitudinal rail integrally attached to said under surface andpositioned below the rider support region of the body portion.
 2. Thesled of claim 1, where the sled comprises at least two longitudinalrails below said rider support region of said body portion.
 3. The sledof claim 1, wherein said body portion further comprises one or morehandles adjacent said rider support region.
 4. The sled of claim 3,further comprising a strap, said strap having one end attachable to saidone or more handles.
 5. The sled of claim 4, wherein said strapcomprises a second end securable to a user.
 6. The sled of claim 1,wherein the elongate member comprises an outer side edge, said outerside edge comprising a region of concave curvature.
 7. The sled of claim1, wherein said elongate member comprises an outer side edge, said outerside edge comprising a convex curve.
 8. The sled of claim 1, whereinsaid elongate member comprises symmetrical side edges.
 9. The sled ofclaim 1, wherein said elongate member comprises two outer side edgeshaving asymmetrical curvature.
 10. The sled of claim 1, wherein saidelongate member comprises an outer side edge has a bevel.
 11. The sledof claim 1, further comprising a top skin on said upper surface.
 12. Thesled of claim 1, wherein the soft foam core extends from the trailingedge of the body portion to the leading edge of the upturned leading endportion.
 13. The sled of claim 1, further comprising a bottom skin onsaid under surface.
 14. The sled of claim 12, wherein said rail is undersaid bottom skin.
 15. The sled of claim 12, wherein said rail is abovesaid bottom skin.
 16. The sled of claim 1, wherein said rail is at leasttwo inches in length.
 17. The sled of claim 1, wherein said body portionhas a length, and said rail has a length substantially equal to thelength of said body portion.
 18. The sled of claim 1, wherein said railhas a depth of 0.1 inches to 2.0 inches.
 19. The sled of claim 1,wherein said rail is a protruding ridge.
 20. The sled of claim 1,wherein said rail an intruding groove.
 21. The sled of claim 1, whereinsaid rail comprises a soft foam core.
 22. The sled of claim 21, whereinthe soft foam core of said rail has a density that is equal to orgreater than the soft foam core of said elongate member.
 23. A sledcomprising an upwardly curved leading portion, an elongate portion, anda self-supporting soft foam core, the elongate portion comprising: (a) asupport section for support of a rider; (b) an upper surface comprisinga top skin; (c) an under surface comprising a bottom skin; and (d) atleast one longitudinally-extending rail integrally secured to the undersurface of the support section of the elongate portion.
 24. The sled ofclaim 23, wherein said bottom skin is a polyethylene film.
 25. A methodfor making a self-supporting, soft foam sled board comprising the stepsof: (a) laminating a soft foam rail piece to a preshaped, soft foam corematerial to form a rail/foam core composite; and (b) laminating a bottomskin to said rail/foam core composite.
 26. The method of claim 25,wherein said bottom skin is polyethylene film.
 27. The method of claim25, wherein said bottom skin is a film/foam laminate prepared bylaminating a polyethylene film to a polyethylene foam sheet to form abottom skin having a foam surface and a film surface.
 28. Aself-supporting, soft foam board for sliding over a surface, comprising:(a) an upper surface; (b) a bottom surface (c) one or more handles andsupport region for a rider; and (d) at least one convolution integral tothe bottom of said board below the rider support region, whereby theconvolution is in contact with the surface when a rider on said ridersupport region pulls on said one or more handles.